Spring for artificial teeth



UNITED sTATEs PATENT OFFICE."

GEO. vSTUART,` or PHILADELPHIA, PENNSYLVANIA.

SPRING FOR ARTIFICIAL TEETH.

Specification of Letters Patent No. 5,181, dated July 3, 1847.

To all whom t may concern.'

Be it kno-wn that I, GEORGE STUART, surgeen-dentist, of the city of Philadelphia, in the State of Pennsylvania, have invented a new and useful manner of constructing springs for connecting and opening sets of artificial teeth that consist of those contained in the upper and lower jaw, which spring I denominate the dental lever-joint spring; and I do hereby declare that the following is a full and exact description thereof.

The spring heretofore employed for connecting and opening the sets of artificial teeth consists simply of what is usually denominated a spiral spring, which is fo-rmed by the winding of a wire aro-und another of suitable size, so as to form a hollow cylinder; this kind of spring is however very imperfect in its operation, and is liable to be misplaced in the mouth in the pro-cess of mastication; from which objections, my improved spring is perfectly free.

In the accompanying drawing Figure 1, is a side view of a set of teeth with my improved lever-jointspring applied thereto. Fig. 2, is an edge view of the spring when separated from the teeth, and opened out so that the two arms of the lever are in a line with each other, and Fig. 3 is a view of that side of it that is toward the teeth when the spring is in use; the spring being in this case also shown as opened out, as in Fig. 2.

In each of these ligures where the same parts are shown they are designated by the same letters of reference.

A, and B, are the two arms of the leverspring; these two arms are formed principally of the uncoiled ends of a wire, the middle portion of which is bent round, so as to form the spiral coil a, a, Fig. 2, and within which there is a round pin, or barrel Fig. 3, which receives a screw cl, Fig. 2, that holds it in place; this screw is suppo-sed to be removed in Fig. 3.

e, Fig. 2, is the head of the pin, or barrel Z9; this barrel tits loosely within the coil a, a, offering no resistance to its action, but merely preventing its becoming disarranged. The upper end of the wire forming the coil a, a, is bent down as shown at a', Fig. 2, and is again bent at right angles so as to enable it to form the arm B, of the lever spring. The portion f, f, of these arms, which appear as though they were spiral springs, are merely elastic tubes that surround the two ends of the wire c, a, which constitute a principal portion of the arms A, B; these spring tubes are unconnected with the wires a, a, at their inner ends, said.`

wires merely passing thro-ugh them, lbut at their outer ends the wire forming the elastic tubes f, f, are soldered to the outer ends of the wires a, a, and with them, and with the ends of the arms A, B, constitute onepiece.

The ends of the arms A, B, are received upon joint pins, or pivots z', c', projecting from the teeth; (Fig. l) there being holes j, j, Fig. 3, through these arms for that purpose. To enable them to pass on to t-he pivot z', i; the ends of the arms are slit, as represented in Fig. 3, so that they may spring open, and the parts are held together by screws a, n, passing through the edge of the arms. The pivots z', z', might, if preferred, be made t-o vproject fro-m the metallic plates m, m, instead of from the teeth.

Connected with one of the arms of the lever-spring there isa plate of gold c, c, one end of which is perforated soas to pass over the barrel or pin b, and to rest upon its head c; its other end is furnished with a pin 0, Fig. 3, that slides in a slot p in the lever arm vB. I/Vithin this slot it has lsufficient play endwise to admit of the necessary elastic action of the arms of thelever springs, while it eifectually prevents their being unduly bent, the arrival of the pino, at either end of the slot` checking all further bending. Without this provision the lever springs might be subject to disagreement. Having thus fully described the manner in which I form, arrange, and combine, the respective parts of my dental lever joint spring, what I claim therein as new, and desire to secure by Letters Patent, is-

The manner of forming the spring joint and arms of said instrument, in the manner herein set forth; that is to say, by the-coiling of the middle of the wire a, a, so as to constitute the spring joint, and the extending of the`outer ends thereof so as, in part, to constitute the elastic arms of the lever, in combination with the check plate c, c, operating in the manner and for the purpose setforth, and in combination also with the sets attaining the same end by means substantially the same.

GEORGE STUART.

Witnesses:

THos. P. JONES, WM. J. DoNoHoo. 

